Short-term effects of filter cake and biochar on the physical-hydric properties of an oxisol

The residues and by-products from sugarcane processing can modify the primary soil structure and promote sustainable cultivation. Understanding the residue-soil interaction in water availability in tropical soils is essential for various economically important crops. Thus, this study aimed to evaluate the effects of filter cake and biochar application on the physicalhydraulic parameters of Oxisol in the short term. A field experiment was conducted on a commercial farm using six strip-plot treatments with four replications: Control; Bc100 (10 Mg ha-1 of biochar); Bc50 (5 Mg ha-1 of biochar); Fc100 (40 Mg ha-1 of filter cake); Fc50 (20 Mg ha-1 of filter cake); and Fc100+Bc100. After one year, soil samples (0-0.1 m layer) were collected and analyzed for bulk density, total porosity, macroporosity, microporosity, and the area under the soil water retention curve (AUWRC). Filter cake and biochar application did not influence soil density in the short term. However, applying 40 Mg ha-1 of filter cake increased total porosity and soil water retention. Additionally, combining 40 Mg ha-1 of filter cake with 10 Mg ha-1 of biochar further enhanced water retention, whereas biochar alone showed no significant effect. The results indicate that filter cake, either alone or in combination with biochar, improves the physical-hydraulic properties of medium-textured soil after one year of application.